Radio based proximity token with multiple antennas

ABSTRACT

A method of detecting a signal ( 10, 10 ′) between a token ( 12 ) and an electronic device ( 14 ) for authorizing a user ( 16 ) to access the electronic device ( 14 ). The method comprises the steps of emitting a signal ( 10, 10 ′) containing data, detecting the signal ( 10, 10 ′) with a plurality of antennas ( 18, 18 ′), and measuring the strength of the signal ( 10, 10 ′) detected at each of the antennas ( 18, 18 ′). If the maximum signal strength detected by any of the antennas ( 18, 18 ′) is above an operational threshold, the electronic device ( 14 ) will be enabled. If the signal ( 10, 10 ′) is above the operational threshold, the signal ( 10, 10 ′) is compared to a user code database for authorizing the user ( 16 ) to access the electronic device ( 14 ). The operational threshold may be lowered to account for any signal variances that may occur after the user ( 16 ) has been authorized to access or when accessing the electronic device ( 14 ).

BACKGROUND OF THE INVENTION

This application claims priority to provisional patent application60/168,406 which was filed Dec. 01, 1999.

FIELD OF THE INVENTION

A method of detecting a signal transmitted between a token and anelectronic device for authorizing a user to access the electronic device

DESCRIPTION OF THE PRIOR ART

One method for providing security for accessing an electronic deviceincludes detecting a signal between a token and an electronic device forauthorizing a user to access the electronic device. The method comprisesthe steps of emitting a signal, detecting the signal with an antenna,and measuring the strength of the signal detected at the antenna. Thesignal is then compared to a predetermined threshold to determine if theuser is within a predetermined range. If the user is determined to bewithin the predetermined range, the user is authorized to access theelectronic device. If the strength of the signal is below thepredetermined threshold, the user is not allowed to access theelectronic device.

One such method is shown in U.S. Pat. No. 5,821,854 for providingsecurity to a personal computer. However, the software used for thismethod frequently locks the computer in response to signal strengthdropping below the predetermined threshold due to the user moving andworking near the computer. If the predetermined threshold is lowered toallow the user more mobility, the computer is less secure because thesignal strength may still be above the predetermined threshold to allowan unauthorized user to access the computer when the user is not inproximity to the computer.

SUMMARY OF THE INVENTION AND ADVANTAGES

The subject invention provides a method of detecting a signal between atoken, i.e. a badge, and an electronic device for authorizing a user toaccess the electronic device. The method comprises the steps of emittinga signal containing data, detecting the signal with a plurality ofantennas, and measuring the strength of the signal detected at each ofthe plurality of antennas. The method is characterized by sensing themaximum signal strength detected at any of the plurality of antennas andenabling the electronic device in response to the maximum signalstrength being above an operational threshold.

Accordingly, the subject invention provides additional security whendetecting a signal between a token and an electronic device forproviding access to a user. The plurality of antennas allows fordetection of the maximum signal strength to overcome any variance thatmay be detected by the user moving or working near the electronicdevice. Additionally, the detection of the multiple signals allows theelectronic device to log all detected signals and to determine thelocation of the user relative to the electronic device. The methodfurther provides additional security to prevent the electronic devicefrom being accessed by an unauthorized user when the user is not inproximity to the electronic device.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a flowchart showing a method of detecting a signal toauthorize a user to access an electronic device;

FIG. 2 is a perspective view of a first embodiment of a user wearing atoken facing away from an electronic device such that the strength ofthe signal is below a predetermined threshold; and

FIG. 3 is a perspective view of a second embodiment of the user wearingthe token and operating the electronic device whereby the signal isbeing detected and the user is authorized to access the electronicdevice.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the Figures, wherein like numerals indicate like orcorresponding parts throughout the several views, a flowchartillustrating a method of detecting a signal 10, 10′ between a token 12,i.e. a badge having a transceiver disposed therein, and an electronicdevice 14 for authorizing a user 16 to access the electronic device 14is shown in FIG. 1.

The method comprises the steps of emitting the signal 10, 10′ containingdata, detecting the 10, 10′ with a first plurality of antennas 18, 18′,and measuring the strength of the signal 10, 10′ detected at each of thefirst plurality of antennas 18, 18′. The signal 10, 10′ is preferablyemitted as a radio frequency (RF) or an equivalent signal that allowsfor wireless communication as is known in the art. A first embodiment,as shown in FIG. 2, emits the signal 10 from the token 12. The secondembodiment, shown in FIG. 3, emits the signal 10′ from the electronicdevice 14. The signal 10, 10′ maybe emitted continuously or periodicallyas is required to provide adequate security and to authorize the user 16for continued access to the electronic device 14. The token 12 may beprogrammed to transmit for a specified period of time and then terminatetransmission for a predetermined period of time. The token 12 may be abadge, a pager, or any other portable unit carried or worn by the user16.

In FIG. 2, the token 12 has a second plurality of antennas 19 positionedtransverse to each other for subsequently emitting the signal 10 fromone of the antennas 19 and then from the other of the antennas 19. InFIG. 3, the electronic device 14 has the second plurality of antennas19′ positioned parallel and transverse to each other for subsequentlyemitting the signal 10′ from one of the antennas 19′ and then from theother of the antennas 19′.

In both embodiments, the first plurality of antennas 18, 18′ are aimedtransversely to each other such that one of the antennas 18, 18′ isaimed in a first direction and the other of the antennas 18, 18′ isaimed in a second direction so that one of the directions is always moresensitive for detecting the signal 10, 10′, that is, except when thesignal direction bisects the antennas 18, 18′. The electronic device 14is preferably a computer but may further include printers, cellularphones, scanners, or any other electronic equipment. The emitted signal10, 10′ is detected by the plurality of antennas 18, 18′. The antennas18, 18′ may be any type of antennas as is known in the art of RF signaldetection. In addition, the antennas 18, 18′ maybe circularly polarizedfor increasing the probability of detecting the other of the antennas19′.

In the first embodiment, shown in FIG. 2, the electronic device 14 has afirst measurement device 20, an first antenna switch 22 and a firstprocessor 24 and the token 12 has an second antenna switch 23, a secondmeasurement device 21 and a second processor 25 to perform the method asdescribed below. In the second embodiment, shown in FIG. 3, the token 12has the first measurement device 20′, the first antenna switch 22′, andthe first processor 24′ and the electronic device 14 has the secondmeasurement device 211, the second antenna switch 23′, and the secondprocessor 25′ to perform the method as described below. It is to beunderstood that the method may be practiced with one way or two waycommunication between the token 12 and the electronic device 14.

After the signal 10, 10′ has been detected by the antennas 18, 18′, thesignal 10, 10′ is sent to a measurement device 20, 20′ for measuring thestrength of the signal 10, 10′ detected. Most likely, each of theantennas 18, 18′ will detect a different signal strength. An antennaswitch 22, 22′ alternates which of the antennas 18, 18′ are beingmeasured for detecting the strength of the signal 10, 10′ to verify thatat least one of the antennas 18, 18′ are receiving a signal strengthabove an operational threshold.

The method is characterized by sensing the maximum signal strength ofthe signal 10, 10′ detected by any of the plurality of antennas 18, 18′and disabling the electronic device 14 in response to the maximum signalstrength falling below the operational threshold. One of the antennas18, 18′ that senses the maximum signal strength is designated as adefault antenna. The antenna switch 22, 22′ is initially positioned atthe default antenna The antennas 18, 18′ are continuously scanned by theantenna switch 22, 22′ for detection of the signal 10, 10′ for measuringthe strength of the signal 10, 10′ and to verify that at least one ofthe antennas 18, 18′ are sensing a signal strength above the operationalthreshold. As the maximum signal strength is detected at a differentantenna than the default antenna, the antenna switch selects the antennaas the new default antenna.

After the maximum signal strength has been sensed, the strength iscompared to the operational threshold. If the signal 10, 10′ detected atany of antennas 18, 18′ is above the operational threshold, the signal10, 10′ detected at the default antenna is transmitted to a processor24, 24′. For example, a signal is detected at a first, default antennaand a second antenna. The signal strength is measured at the firstantenna and the second antenna and the signal strength at the firstantenna is compared to the operational threshold. If the signal strengthat the first antenna is above the threshold, then the signal detected atthe first antenna is transmitted to the processor 24, 24′ and the firstantenna remains the default antenna. If the signal strength at the firstantenna is below the operational threshold, then the signal strength atthe second antenna is compared to the operational threshold. If thesignal strength at the second antenna is above the operationalthreshold, the signal detected at the first antenna is sent to theprocessor 24, 24′ and the second antenna becomes the default antenna.Even if the signal strength at the first antenna is above theoperational threshold, the signal strength at the second antenna will betransmitted to the processor 24, 24′ for establishing the defaultantenna for subsequent detection. If the signal strength at the secondantenna is stronger than that detected at the first antenna, then thesecond antenna becomes the default antenna. When the signal strengthmeasured at every antennas 18, 18′ falls below the operationalthreshold, the electronic device 14 is disabled.

The processor 24, 24′ compares data of the signal 10, 10′ to a user codedatabase. If the data of the signal 10, 10′ matches a user code in theuser code database, the electronic device 14 is enabled and the user 16is authorized to access the electronic device 14. If the signal 10,10′fails to match the user code, the electronic device 14 is disabledand the user 16 is unable to access the electronic device 14. If themaximum signal strength detected at one of the antennas 18, 18′ is belowthe operational threshold, the electronic device 14 remains disabled andthe user 16 is unable to access the electronic device 14. The antennas18, 18′ continuously detect signals from a plurality of tokens that arewithin range of the electronic device 14.

The processor 24, 24′ receives signal information for each of the tokens12 including which one of the first plurality of antennas 18, 18′ whichdetected the signal 10, 10′, the one of the second plurality of antennas19, 19′ which emitted the signal 10, 10′, the signal strength detectedat the first antenna 18, 18′, and the signal strength detected at thesecond antenna 18, 18′. For example, if the signal strength detected byany of the antennas 18, 18′ is above the operational threshold for aplurality of user 16 each having the token 12, each of the users will beauthorized to access the electronic device 14. If more than one user 16is authorized to operate the electronic device 14, the electronic device14 can only be operated by the first user 16 who identified himself byway of logging into the computer. This is accomplished by passwordentry, biometrics, or any other method as is known in the art ofverifying a users identity. If only one user 16 is authorized to use theelectronic device 14 and that user 16 then identifies himself to theelectronic device 14, the electronic device 14 can only be accessed bythat user 16. Meanwhile, the plurality of antennas 18, 18′ are stilldetecting each of the user signals, but the processor 24, 24′, will notrespond to the signal. Once the user 16 logs out of the electronicdevice 14 or his signal strength falls below the operational threshold,the processor 24, 24′ will then respond to the detection of the otherusers signals. The processor 24, 24′ examines the signal information anddetermines if any of the users signals are not detected. The processor24, 24′ also maintains a log of the signal information for determiningwhat tokens 12 are in the operating space and when the signal 10, 10′ isnot detected.

As the user 16 moves about the electronic device 14, the strength of thesignal 10, 10′ can vary with the position and direction the user 16 isfacing. The strength of the signal 10, 10′ is lower when the user 16faces away from the electronic device 14, as shown in FIG. 2, or whenthe signal 10, 10′ is being blocked by the user 16 or any other object.Therefore, the operational threshold may be changed to account for suchvariances in the signal strength after the user 16 has been authorizedor when accessing the electronic device 14. The changes to theoperational threshold are determined by the level of security and arepreprogrammed into the processor 24, 24′. For instance, the operationalthreshold may be lowered in response to the signal 10, 10′ matching auser code in the user code database when the maximum signal strengthdetected is above the operational threshold. The operational thresholdmay also be changed when the user 16 operates a peripheral componentconnected to the electronic device 14. In one embodiment, theoperational threshold may be lowered for a computer when the user 16manipulates a keyboard 26 or a mouse 28.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. The invention may bepracticed otherwise than as specifically described within the scope ofthe appended claims, wherein that which is prior art is antecedent tothe novelty set forth in the “characterized by” clause. The novelty ismeant to be particularly and distinctly recited in the “characterizedby” clause whereas the antecedent recitations merely set forth the oldand well-known combination in which the invention resides. Theseantecedent recitations should be interpreted to cover any combination inwhich the incentive novelty exercises its utility. In addition, thereference numerals in the claims are merely for convenience and are notto be read in any way as limiting.

What is claimed is:
 1. A method of detecting a signal between a tokenand an electronic device for authorizing a user to access the electronicdevice, said method comprising the steps of; emitting a signal (10, 10′)containing data from at least one of a token (12) and an electronicdevice (14), detecting the same signal (10, 10′) with each of a firstplurality of antennas (18, 18′) disposed within the other of the token(12) and the electronic device (14), measuring the strength of the samesignal (10, 10′) detected at each of the first plurality of antennas(18, 18′) with a measurement device (20, 20′), sensing the maximumsignal strength detected by any of the first plurality of antennas (18,18′), and enabling the electronic device (14) to allow the user accessin response to the maximum signal strength being above an operationalthreshold to overcome variances in signal strength in response torelative movement between the token (12) and the electronic device (14)to remain enabled so long as at least one antenna (18, 18′) detects thesame signal (10, 10′) and measures the maximum signal strength above theoperational threshold.
 2. A method as set forth in claim 1 wherein themeasuring is further characterized by scanning the first plurality ofantennas (18, 18′) for sequentially measuring the strength of the signal(10, 10′) at each antenna and isolating the antenna measuring themaximum signal strength as a default antenna such that the defaultantenna is the first one of the plurality of antennas (18, 18′) todetect the signal (10, 10′) upon subsequent emissions.
 3. A method asset forth in claim 2 further characterized by comparing the data of thesignal (10, 10′) detected at the default antenna to a user code databaseand enabling the electronic device (14) for authorizing a user (16) toaccess the electronic device (14).
 4. A method as set forth in claim 3further characterized by changing the operational threshold in responseto the data of the signal (10, 10′) matching a user code in the usercode database.
 5. A method as set forth in claim 4 further characterizedby changing the operational threshold in response to operation of theelectronic device (14) by the user (16).
 6. A method as set forth inclaim 4 wherein the changing of the operational threshold is furtherdefined by lowering the operational threshold.
 7. A method as set forthin claim 6 wherein the changing of the operational threshold is furtherdefined as lowering the threshold in response to input to the computerfrom one of a keyboard (26) and a mouse (28).
 8. A method as set forthin claim 2 further defined as emitting the signal (10, 10′) from theelectronic device (14) and measuring the strength of the signal andsensing the maximum signal strength by a token (12).
 9. A method as setforth in claim 2 further defined as emitting the signal (10, 10′) fromthe token (12) and measuring the strength of the signal and sensing themaximum signal strength by the electronic device (14).
 10. A method asset forth in claim 2 further characterized by aiming one of the firstplurality of antennas (18, 18′) in a first direction and an other of thefirst plurality of antennas (18, 18′) in a second direction, the firstdirection being transverse to the second direction and such that one ofeither the first direction and the second direction is more sensitivefor detecting the signal (10, 10′) than the other direction.
 11. Amethod as set forth in claim 2 wherein the emitting of the signal (10,10′) is further defined as emitting the signal (10, 10′) from a secondplurality of antennas (19, 19′).
 12. A method as set forth in claim 11wherein the emitting of the signal (10, 10′) from the second pluralityof antennas (19, 19′) is further defined as alternating the emission ofthe signal (10, 10′) from one of the second plurality of antennas (19,19′) and then from the other of the second plurality of antennas (19,19′).
 13. A method as set forth in claim 12 including sequentiallydetecting each of the signals (10, 10′) emitted from the secondplurality of antennas (19, 19′) and measuring the strength of thesequential signals (10, 10′) with the first plurality of antennas (18,18′).
 14. A method of detecting a signal between a token and anelectronic device for authorizing a user to access the electronicdevice, said method comprising the steps of; emitting a signal (10,10′), detecting the signal (10, 10′) with at least one antenna,measuring the strength of the signal (10, 10′) detected by the antenna,comparing the strength of the signal (10, 10′) to an operationalthreshold, enabling the electronic device (14) to allow the user accessin response to the signal strength being above the operationalthreshold, changing the operational threshold in response to the user(16) manipulating the electronic device (14) such that variances in thesignal strength allow the electronic device (14) to remain enabled solong as the user is using the electronic device (14), restoring theoperational threshold to the prior value before changing when the userceases using the electronic device (14).
 15. A method as set forth inclaim 14 wherein the changing of the operational threshold is furtherdefined by lowering the operational threshold.
 16. A method as set forthin claim 15 wherein the enabling of the electronic device (14) isfurther defined as enabling a computer.
 17. A method as set forth inclaim 16 wherein the changing of the operational threshold is furtherdefined as lowering the threshold in response to input to the computerfrom one of a keyboard (26) and a mouse (28).
 18. A method as set forthin claim 14 wherein the detecting of the signal (10, 10′) includesdetecting the signal (10, 10′) with a plurality of antennas (18, 18′).